The oil industry has long used whipstocks in drilling to direct a drill bit or cutter at an angle from the well bore and also for side tracking operations, that is, offsetting the well bore from its old direction. U.S. Pat. No. 2,498,159 discloses a whipstock design and indicates the large use of whipstocks in drilling.
At times, it is desirable to set a whipstock in casing at a point substantially above the bottom of the well bore. Previously, whipstocks have been set in casing above the bottom by lowering an anchor-packer on a well string and setting it at the desired level in the well bore, recovering the well string, surveying the set position of the anchor-packer, setting the connector on the whipstock at the surface so that when the connector engages the anchor-packer the whipstock is properly oriented, lowering the whipstock, connector and cutter in the well bore and landing the connector on the anchor-packer to orient the whipstock and support the whipstock for directing the cutter in the preselected direction with respect to the well bore.
The separate trips of well strings for setting the anchor-packer and then lowering the whipstock and cutter is expensive and time consuming.